Scraper ejector mechanism



H. W. ROCKWELL. ETAL SCRAPER v EJECTOR MECHANISM March 4, 1969 Sheet Filed Sept. 26, 1966 March 4, 1969 H. w. ROCKWELL ETAL 3,430,367

SCRAPER EJECTOR MECHANISM Filed Sept. 26, 1966 Sheet 2 or 2 BMW/W:

EM PW Q Q R I 5 9 4 he! @QE 4 United States Patent 6 Claims ABSTRACT OF THE DISCLOSURE A special linkage supports and guides the ejector structure of an earthmover in a predetermined path through the bowl thereof. The linkage includes a pair of downwardly directed, longitudinally spaced links pivotally connected at their upper ends to the ejector structure and supported from the bowl structure at their lower ends. The hydraulic ram for actuating the ejector structure has one end pivoted to the ejector structure and the other end pivoted to one of the downwardly directed links. The bottom end of the other of the downwardly directed links is guided by two links, one of which pivotally connects to the bowl structure and the other of which pivotally connects to said one downwardly directed link.

The present invention relates to earth-moving machinery and especially to scrapers, and it is particularly adaptable to scrapers of the bowl type in which a chamber or bowl having a sharp lower lip or cutting edge is filled with earth by propelling it along the ground with the blade in penetrating relation thereto. When the bowl is full a gate-like apron is dropped in front of the load in the region of the lip, the bowl is raised and the machine is driven to a desired discharge point. The apron is then lifted and an ejector blade structure forming the back wall of the bowl is moved forward to push the load out over the lip, which is raised out of contact with the ground. conventionally the ejecting is done while the machine is in motion, thereby distributing the material in an even layer, as is desirable, and a particular object of this invention is to improve the ejector blade structure and the mechanism for operating it.

Scrapers of this type have supporting wheels rearwardly of the bowl, and it is desirable to have such wheels incorporated in a supporting unit which is readily removed and replaced with one of a modified type, such as a two wheel power module, so that machines which are adapted for varying conditions of operation may be readily supplied by the factory. For example some conditions would require only supporting wheels at the rear, while others might require power driven wheels on a supporting unit to assist the power unit commonly incorporated in the front end of the machine. A further object of this invention is to supply a mechanism for moving the ejector blade which is of such proportions that it may be readily incorporated substantially entirely in the space between the back of the bowl andv the exchangeable wheel unit; that will not have any parts that extend backwardly for enough to interfere with the attachment and detachment of the wheel unit, nor any that will interfere with access to the engine when an engine unit is used.

A further object of this invention is to provide an ejector mechanism which does not require sliding guides 3,430,367 Patented Mar. 4, 1969 ice of any kind within or without the bowl for vertically positioning the ejector structure; which gives a substantially complementary movement of the blade along the floor of the bowl; and in which the blade is given a gradually changing inclination, from approximately vertical when at the rear of the bowl to appreciably backwardly inclined when at the front of the bowl, so as to avoid compressing the material against the apron during ejection.

A further object of this invention is to provide an ejector mechanism which may be activated by an expansible motor or ram of reasonable proportions and in which the force of the ram is applied with greatly varying leverage, so that the force is largely multiplied at the time of starting to eject the load, but becomes less and less during ejection in approximate correspondence to the reducing force requirement therefor.

Further objects and advantages will become apparent from the following description when read in conjunction with the accompanying drawings in which:

FIG. 1 is a plan view of an earthmover embodying the invention;

FIG. 2 is a left side elevation of the same with parts broken away to better show the ejection mechanism;

FIG. 3 is an enlarged detail of a portion of the ejector mechanism shown in FIG. 2 with the elements in a different position and with some parts shown in section; and

FIG. 4 is an enlarged sectional view taken on the line IV-1V of FIG. 2 with some parts omitted.

Referring to FIGS. 1 and 2, the earthmover comprises a tractor portion 10 constituting the main propulsion means for the machine connected by a pivot 12 to a gooseneck 14 forming part of a bowl structure generally designated as 16. Bowl structure 16 is supported at its rear end by a supporting wheel unit designated in its entirety as 18 and which is adapted to be readily removed and replaced with a ditferent type if desired. Tractor portion 10 has wheels 20 and other essential parts not necessary to show and describe while unit 18 has wheels 22 and 23 and in the present instance an engine 24 which is connected with the wheels to drive them and assist the propelling action of tractor portion 10. Suitable controls are provided to coordinate the action of tractor 10 and engine 24 but which are well known and form no part of the present invention.

Bowl portion 16 has upstanding side walls 26 and 28 and a floor or bottom portion 30, wall portion 28 having a pivot 32 by means of which it is connected to an arm 34 extending along side wall 28 forwardly and fixed on a portion 36 of gooseneck 14. A similar arm 38 is connected to wall 26 on a pivot 40 and fixed to a portion 42 of gooseneck 14, the whole forming a yoke arrangement about the forward end of bowl structure 16 so that the bowl may be rocked up and down about pivots 32 and 40 with coincidental rocking of tractor 10 and supporting wheel unit 18.

It is to be understood that tractor 10' is a well known type having only wheels 2020 and is stabilized solely by its pivotal connection 12 with gooseneck 14.

As so far described the machine would be unstable. However, a yoke-like structural portion 44 of walls 28 and 26 extends forwardly to a region beneath the rear portion of gooseneck 14 and is connected through a pivot 46 with a fluid motor 48 connected by pivot 50 to a portion of gooseneck 14. Actuation of motor 48 by suitable controls not shown will raise and lower portion 3 44 and thereby pivot bowl structure 16 about aligned pivots 32 and 40.

Beneath pivots 32 and 40 bowl structure 16 has a transversely extending lip portion 52 which is provided with a sharp cutting edge 54 (see also FIG. 3) and which inclines downwardly and forwardly from floor 30 so as to contact the ground when pivots 32 and 40 are sufliciently lowered. A gate or apron structure 56 is arranged to rest on lip 52 and has rearwardly extending arms 58 and 60 close to walls 28 and 26, respectively, and having pivotal connections 62 and 64 therewith so that apron 56 may be swung upwardly away from lip 52 when desired. For so swinging apron 56 a lever arm 66 is supported on a pivot 68 on a bracket 70 carried on gooseneck 14. Arm

66 has a pivot 72 carrying a link 74 which extends downwardly to a pivot 76 carried on a portion 78 of apron structure 56. An expansible fluid motor 80 is supported on a pivot 82 on gooseneck 14 and has its other end pivoted to a portion of lever arm 66 on a pivot 84. Expansion of motor 80 by means of well known controls not shown will therefore cause raising of apron structure 56. A plate-like ejector blade 86 is shaped to conform with the interior of bowl 16 as defined between walls 26, 28, and floor 30 and, in the position shown in FIGS. 1 and 2, forms a back wall for the bowl. Blade 86 is movable in bowl 16 from the FIG. 2 position to the position shown in FIG. 3 by certain mechanism which will be described, and such movement is ordinarily performed with apron 56 in the raised position shown in FIG. 3. Guiding and propelling plate 86 is difiicult and various mechanisms have been designed for this purpose, all of which, however, left something to be desired.

In the present instance the guiding is done entirely by swinging links which are so constituted as to guide the blade substantially in a path conforming to the contour of the bowl, in the present instance in a straight line so that there is no need for any contact with the bowl in order to guide the blade. It is contemplated that it is possible to have the blade follow the contour of the bowl with slight clearance so as to avoid wear and unnecessary friction. However, if wear or any lack of precision in the fabrication of the parts causes cont-act between the blade and the bowl no serious harm will be done as any such contact will be comparatively light, the major force being sustained by the linkage. The linkage is carried entirely on bowl structure 16 which has a pair of rearwardly extending struts or sills 88 and 90 at approximately the level of floor 30. It also has a heavy upper cross member 92 connected to sills 88 and 90 by means of struts as 94 forming a strong rearward extension of the structure to which can be attached in any suitable manner above mentioned engine and supporting wheel unit 18.

As hereinbefore indicated a similar unit without engine 24 may be substituted for unit 18 and the linkage to be described is supported on sills 88 and 90 and also on cross member 92.

Blade 86 has rigidly and ruggedly fixed on the rear face thereof a pair of laterally spaced brackets 96 and 98 which extend rearwardly and which incorporate upper re rwardly extending arms 100 and 102 and which are rugged enough to take the major part of the stress involved in guiding ejector blade 86 against the resistance of a heavy load, arms 100 and 102 guided by swinging links in such a manner as to restrain ejector blade 86 from any but the desired path of movement within bowl structure 16. Brackets 96 and 98 are preferably identical and the links controlling them are duplicated on the two sides of the machine, so where practical only one side will be described, it being understood that the other side is exactly similar. Briefly, a link 104 pivoted on a lower pivot 106 carried on sill 88 connects through an upper pivot 108 with the rear extremity of arm 100 forming part of bracket 96. Also a link 110 suitably supported on a pivot structure 112 connects through a pivot 114, FIG. 4, with a bracket 116 fixed on a frame member 118 forming part of ejector blade 86. The effect is similar to what it would be if link were pivoted to the forward end of arm 100 while link 104 were pivoted to the rear end of arm 100.

In other words fore and aft swinging of link 104 will cause fore and aft movement of arm 100 and blade 86, and which movement is guided by swinging of link 110. As hereinbefore stated this structure is duplicated on the two sides of the machine.

Thus link 104 has its counterpart 120 supported on a pivot 122 on sill 90 and which connects through a pivot 124 with arm 102. Similarly a link 126 also supported on pivot structure 112 connects through a pivot 128 with a bracket 130 fixed on frame member 118.

Links 104 and 120 are connected by a rugged torsion resisting cross member 132 so that for all practical purposes they are rigidly fastened together and swing in a common plane about pivots 106 and 122. Any tendency of ejector blade 86 to twist or get out of proper position in bowl structure 16 is therefore strongly resisted by links 104 and 120 through torsion resisting member 132 since such misalignment of blade 86 would rock one of links 104 and 120 more than the other, which is impossible without twisting member 132. In other words member 132 prevent-s link 104 from swinging any different amount than link 120 so that misalignment of blade 86 is impossible so long as the parts remain intact.

It is desirable to make bowl structure, or more properly floor 30 straight since this is convenient in fabricating the parts. However, the mechanism so far described would result in a curved path for blade 86. Pivot structure 112 however is not fixed in position but is shiftable, and which shifting modifies the path of the upper pivots 114 and 128 to produce substantially the straight line movement of the blade which is desired to conform with the shape of floor 30.

'Pivot structure 112 comprises a rugged T-head or cross piece 134 which is preferably rigidly connected to a link portion 136 carried on a pivot 138 supported on a bracket 140 fixed on above mentioned frame member 92. Pivot 138 is therefore located substantially above and a little forwardly of pivots 106 and 122, in the present instance. It will now be apparent that pivot structure 112, while movable, can move only in an arcuate path about pivot 138 'as a center. However, by controlling the amount of this movement, the resultant movement of links 110 and 126 may be controlled so that it is possible to obtain substantially any path of movement desired in pivots 114 and 128.

Pivot structure 112 has pintles 141 and 142 at the ends thereof, link 110 being pivoted on pintle 141 and link 126 being pivoted on pintle 142. An offset link 144 is pivoted on pintle 141, in the present instance outside of link 110, and is also pivoted on 'a pivot 146 to a bracket 148 fixed on torsion resisting member 132 and extending generally in the same directioin as links 104 and 120 or upwardly and rearwardly in FIGS. 2 and 4 about midway between links 104 and 120. A second offset link 150 connects above mentioned pivot 146 with pintle 142 so that the extremities of pivot structure 112 are controlled through links 144 and 150 by the swinging movement of bracket 148, the efiect being similar to what would be the case if pivot structure 112 were connected to links 104 and 120 part way between pivots 106 and 108, or 122 and 124, respectively.

By suitably choosing the length of arm 100 links 104 and 110, and link 144, together with the locations of pivots 114, 108, 141, 146 and 138 a variety of paths of movement may be obtained in ejector blade 86, these links and locations in the present instance being such as to result in a substantially straight line movement of blade 86 and it is contemplated that the path will be such or may be such as to provide slight clearance about blade 86 on all sides between it and walls 26, 28 and floor 30. However, if desired or by reason of deterioration of the parts or lack of precision in manufacture blade 86 does touch one of the elements of bowl 16, the contact would be minor and the burden of guiding blade 86 would still be assumed by the linkage, the heavy stresses being carried on the several links and pivots.

As stated, a variety of paths of movement may be obtained in blade 86, and it is desirable that the angle of the blade in relation to floor 30 may change slightly as the blade advances. Thus in the position of the parts while the bowl is being loaded and blade 86 forms the rear wall, it is generally at right angles or normal to floor 30. As blade 86 progresses toward lip 52, however, its angle changes until at the end of the ejecting movement, namely the FIG. 3 position of the parts, the blade slants backwardly in relation to floor 30 a predetermined substantial amount. This will avoid a tendency which would otherwise exist to compress the earth or material in the bowl when it is attempted to remove it, which would add substantially to the force required, would tend to pack or compact the material, and would otherwise be undesirable. The several links and locations of the pivots are such as to produce this gradual rearward inclination as the ejector blade progresses toward lip 52.

This completes the description of the guiding linkage.

The motion of blade 86 is caused by expansible motors 152 and 154, motor 152 having a piston rod 156 connected by a pivot 158 and a bracket 160 with frame member 118. A bracket 162 on motor 152 connects by means of a pivot 164 with an arm 166 rigidly fixed on above mentioned pivot 106 so as to partake of the movements of link 104. Regardless of the fact that such a connection tends to work backwardly against the swinging of link 104 it will be apparent that the distance between pivots 164 and 158 is much greater when blade 86 is in the FIG. 3 position than it is when blade 86 is in the FIG. 2 position. This being true it follows that expansion of motor 152 will cause forward motion of blade 86 and forward swinging of link 104 and bracket 166. In order to stiffen the structure a torsion member 168 is interposed and rigidl fixed between link 104 and arm 166. It is to be understood that motor 154 is connected to link 120 and frame member 118 in a substantially identical manner.

In operation the machine is propelled along the ground by the action of tractor portion and engine 24 (if so supplied) apron 56 is raised by action of fluid motor 80 and lip 52 is lowered to the ground by operation of fluid motor 48. At this time ejector blade 86 will be at the rear end of bowl structure 16 and earth will be raised by lip 52 and accumulate on floor 30 ahead of blade 86. When suflicient earth has been accumulated, or in other words when bowl 16 is full, apron 56 is lowered while lip 52 is raised off the ground by action of fluid motors 80 and 48, respectively. The machine is then driven to a desired point of discharge whereupon apron 56 is again raised by action of fluid motor 80 and ejector blade 86 is urged forwardly by actuation of fluid motors 152 and 154. In,

view of the fact that the angle between link 104 and arm 100 is relatively small at the beginning of this action as seen in FIG. 2 a predetermined amount of force developed by motor 152 will exert a very large pressure against ejector blade 86. As the ejecting process continues the angle between link 104 and arm 100 becomes greater so that motor 152 is pushing more generally in the direction of link 104 and arm 100. This tends to reduce the force applied to blade 86 compared to that developed by motor 152 and to reduce the distance traveled by piston rod 156 compared to the distance traveled by blade 86, as the movement continues. The change in the ratio of force and movement continues to the end of the stroke of the motor and the extreme position of arm 100 and link 104 which are now disposed substantially lengthwise of each other.

In other words motor 152 has a favorable leverage against arm 86 at the beginning of the movement and which leverage becomes less and less favorable as the movement continues. This is desirable since the load spills off over lip 52 and the resistance to movement becomes less and less as the movement continues. Furthermore the change in leverage results in less and less travel of motor piston rod 156 for a given resultant travel of blade 86. In this way sufficient travel of blade 86 can be obtained with a very short motor or ram.

The supporting of motor 152 on arm 166 causes the motor portion to be shifted in the direction in which the piston rod is expected to move. The effective stroke of piston rod 156 is therefore lengthened to the extent of the swinging movement of arm 166 which tends to displace the whole of motor 152 in the desired direction. In this way a longer effective stroke of the motor is achieved than would be possible if the motor were supported on a fixed pivot or part of bowl structure 16. A motor of reasonable length is therefore all that is required and not one of substantially twice the desired stroke or movement of blade 86 as common in some past structures. Furthermore the whole linkage extends rearwardly only slightly past the point of attaching of wheel unit 18.

From the above it will be apparent that a linkage hasbeen provided which will give a straight line or other desired motion to an ejector blade; which will require a minimum of space behind the blade; which will require no guides of any kind in the bowl structure; and which will utilize motor means of reasonable size and proportions.

While a specific application of the invention has been described in detail, it is to be understood that variations are contemplated and that all such as come within the scope of the claims are intended to be covered.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A scraper of the type having a carrying bowl structure of predetermined cross section, an ejector blade structure including a blade complementary in shape to said cross section disposed transversely to said bowl structure and in one position forming a rear wall therefor, and linkage connected to said blade structure and to said bowl structure supporting said blade structure and guiding said blade in a predetermined ejection path through said bowl structure conforming to the contour of the latter, said linkage including a pair of downwardly directed links having their upper portions pivotally connected to said blade structure at points spaced longitudinally thereof and pivotally supported at their lower ends from said bowl structure, one of said downwardly directed links including a pivot and means for supportin the pivot from said bowl structure, which means is shiftable during movement of the blade to modify the path of travel of the upper pivotal connection of said one link in relation to the upper pivot connection of the other of said links whereby to control the movement of said ejector blade to follow said predetermined ejection path.

2. A scraper having all the characteristics of claim 1 including means connected with said pivot and with the other downwardly directed link for shifting said pivot in response to swinging of said other downwardly directed link to modify the path of travel of said upper pivotal connection of said one link in relation to the upper pivot connection of the other of said links whereby said pivot will be shifted in accordance with swinging of said other link.

3. A scraper having all the characteristics of claim 1 in which said means for supporting said pivot comprises an upwardly directed link connected to said pivot and pivoted to said bowl structure in a region above said pivot, whereby the swinging of said upwardly directed link will shift said pivot and modify the path of travel of said one downwardly directed link.

4. A scraper having all the characteristics of claim 3 including means connected with said upwardly directed link and with the other downwardly directed link for shifting said pivot in response to swinging of said other downwardly directed link, whereby said pivot will be shifted in accordance with swinging of said other link.

5. A scraper having all the characteristics of claim 1 including means for swinging said downwardly directed links comprising an expansible motor having one end connected to said blade structure in the region of the upper end of said one link, and the other end supported from said bowl structure in the region of the lower end of the other link, whereby expansion and contraction of said motor will cause swinging of said links and travel of said blade in the direction determined by said links.

6. A scraper having all the characteristics of claim 1 in which said blade structure includes a pair of laterally spaced rearwardly directed supporting arms rigidly attached to and extending from an upper portion thereof and wherein said linkage includes two laterally spaced downwardly directed links having their upper portions pivoted, respectively, to rear ends of said arms and pivotally connected at their lower ends on said bowl struc- References Cited UNITED STATES PATENTS 2,169,946 8/1939 Frentzel et al 37126 2,226,859 12/1940 French 37-126 2,445,053 7/1948 Allin 37126 2,994,976 8/1961 Hancock 37-126 3,325,925 6/1967 Hermiz et al 37126 XR EDGAR S. BURR, Primary Examiner.

US. Cl. X.R.

ture to support said rearwardly directed arms and a 20 70 

